Process of producing multi-layer paper, cardboard, pasteboard, boxboard and the like, and product thereof



! Patented Dec. 17, 1935 PROCESS OF PRODUCING MULTI-LAYER PAPER, CARDBOARD, PASTEBOARD, BOX BOARD AND THE LIKE, AND PRODUCT THEREOF Ernst Fues, Hanau-on-the-Main, Germ any, as-

signor to Anthony William Delle'r, Brooklyn,

No Drawing. Application August 26, 1932, Serial No. 630,532. In Germany July 27, 1931 10 Claims.

The present invention relates to .a process of producing paper and more particularly to a process of producing multi-layer paper, cardboard, boxboard'and the like and to products 6 thereof. I

Heretofore, various types of printing paper especially for art printing, off-set printing, autoprinting and the like have been'made of paper, 1 cardboard, pasteboard, millboard, boxboard and the like which have been coated with a" mixture of a mineral such as chalk, blanc fixe, China clay and the like and a binder such as glue and the like together with other additions like filler materials or light-sensitive emulsions. As is well known the production of the so-called chrome and blanc fixe paper, cardboard, pasteboard and the like has been cumbersome, complicated, bothersome and expensive and has usually involved operations or fabrication at two different and independent factories or plants. In other words, the paper has been made at one factory and then has been treated or coated at a second factory. This prior procedure involved among other things drying the paper at the first paper factory and then re-drying the coated paper at the second factory after the coating operations. Those skilled in the art have been aware of the disadvantages and shortcomings of prior processes and products and have been searching for a solution to the outstand'-.

ing problem confronting the art. As far as I am aware, however, the art has not been prov vided with a wholly satisfactory and practicalprocess and product.

I have discovered a process which overcomes the disadvantages and shortcomings of prior processes and whichprovides the art with an improved product.

It is an object of the present invention to provide a process of producing a multi-layer which is simple and economical and which is capable of being carried into, practice comdescription of a preferred embodiment of the invention.

Broadly stated, the process contemplates the provision of a special surface to at least one face of a sheet of paper, cardboard, pasteboard and 5 the like. In embodiments of the invention involving a multi-layer structure, the special surface is provided between the layers. It has been discovered that the aforesaid special surface may be made by the preparation of a slippery, pastelike mass of ground or macerated fibrous material and a mineral filler and/or coloring material. I have found that when the aforesaid mass contains an excessive quantity of mineral filler and/or coloring material, especially in excess'of 15 amounts ordinarily employed, unexpected, new and improved results are obtained, particularly in the art of printing. By applying a superfine, slippery, paste-like mass of the foregoing type to a sheet of paper or the like and then treating 20 the coated sheet to appropriate operations including heat and pressure, an integral unit is produced.

For the purpose of giving those skilled in the art a better understanding of theinvention, the 25 following description of a preferred procedure of carrying the invention into practice will be given.

It is preferred to prepare a slippery, paste-like mass of fibrous material, such as wood fibers,

and solid particles, such asmineral fillers, color- 30 ing agents and the like by wet grinding or macerating the constituents to an excessive degree. The purpose of this excessive grinding is to produce a new superfine mass capable of being applied to a sheet of paper, cardboard, paste- 35 board and the like to produce a new surface especially valuable and useful in connection with printing. This unique mass is applied to a sheet of ordinary paper, cardboard, pasteboard and the like, preferably at the paper factory where the sheetis being made and while the sheet is still .moist and/or wet. By proceeding in this manner an excellent bond is established between the paper and the applied coating or layer of slippery or paste-like mass. If amulti-layer structure, the mass is applied between adjacent sheets of thepile or layer. In addition at least one exposed surface of the multi-layer structure is coated and preferably both exposedfaces are coated. The entire sheet or multi-layer structure is subjected to operations to amalgamate the mass into an integral unit. Thus by drying and pressing as in a paper making maby means of glue.

ucts, the new product has a surface integral with du'ced.

. It is to be noted that it is within the contemplation of the invention to provide a new product which replaces old products, such as paper, etc. having chromo-films affixed thereto In contrast to the old prodand amalgamated to the foundation sheet, etc. which contains superfine fibers, filling material, light-sensitive particles, coloring material, etc. In passing, it is to be noted that the new product can be produced in one operation and can be made with one or two treated surfaces. The amalgamating can be effected by couching between upper and lower screens in a so-called Diana apparatus and by removing the material on the screens by means of sucking boxes or roller. Of course, other appropriate or equivalent operations may be employed.

It is to be noted that the present invention can be used for improving all kinds of lower grade papers, cardboard, pasteboard, etc. These papers, etc. will get a glossy and easily printable surface. Furthermore, the color, the appearance, and the translucency of the paper are improved.

It is a further feature of the invention that the intermediate layers of a multi-layer structure for producing a high grade product having a white appearance. This .is true even if the paper, etc. which is used is relatively dark. Thus thin chromo-substitute papers can be made by the present invention.

In conjunction with the opaque masses which are applied to a paper, other materials can be added such as inorganic and organic colloids like silicates, soaps, etc. Such additional'materials can be added for improving the surface finish, the behavior of the fin hed product toward printing inks, etc. and the glossing of the surfaces.

In some cases, it has been found especially advisable to use in the opaque, slippery pastelike mass exceedingly finely dispersed particles such as filler, mineral and color substances. By employing such additional materials the opacity of the coating layer is improved. Such fine dispersion can be achieved by precipitating the filling, coloring, etc'. material within the slippery, paste-like mass. Furthermore, it is sometimes advisable to precipitate the colloids which in some cases are to be added within the fibrous material or other constituents of the paste-like mass. This precipitgion can be effected in the so-called Hollander or in the step between the Hollander and the paper machine or even on the paper machine. In some cases, it may be desirable to use the process described in German Patent No. 514,921 (dated November 25, 1930).

In using a highly weighted surface for a sheet of paper, the products produced according to the invention not only contemplate substitutes. for the known painted, chromoyand barytes papers, cartons, etc. but contemplates excelling such old products due to the fact that the filling and coloring agents are tenaciously held in the opacity layer of the sheet of paper, etc. This structure is far superior to the old one made with glue, etc. In other words, the present product .involves a foundation sheet, etc. to which an opacity layer is interlocked and tenaciously united. It is clean therefore that the new products do not break on sharp corners, edges, etc., are free from tension, lay very smoothly, do not split or chip off when worked or handled. It is important to note that the aforesaid disadvantages frequently occur if glue is only used as a binder. Moreover, it is a feature of the invention to provide a with drawn or bailed paper.

I claim:

1. The process of producing integral paper product which comprises forming a hydrated cellulosic slippery mass having a fibrous structure and containing a mineral filler, applying said mass to the surface of a wet paper web, and finishing said web to form an integral product.

2. The process of producing integral paper product which comprises grinding cellulose pulp 15 to form a hydrated cellulosic slippery mass having'a finely divided fibrous structure, incorporating a filler wholly of mineral character in said mass in excessive amounts, applying said mass to a web of paper in wet condition, and uniting said 20 mass to said web of paper to produce an integral product. a

3. The process of producing an integral paper unit which comprises grinding wet cellulose pulp to form a finely divided, hydrated cellulose mass having a fibrous structure, incorporating a quantity of mineral filler in said mass in excess of amounts ordinarily employed, applying said mass to a web of paper in a wet condition, and amalamating said web under heat and pressure to produce an integral unit.

4. The processs of producing an integral paper unit which comprises applying a mass of finely divided, hydrated cellulose having a fibrous structure and containing a large amount of a mineral filler to a web of paper in a wet condition, and uniting said mass to said web of paper to produce an integral unit.

5. The process of producing a multi-layer paper product which comprises grinding cellulose fibers in the presence of water to an excessive extent to produce finely divided, slippery, hydrated cellulose having a fibrous character, incorporating a large quantity of mineral filler in an amount greater than that ordinarily employed, applying said finely divided, hydrated cellulose fibers to a web of paper in a wet condition, uniting, said mass to said web of paper to amalgamate the two together, continuing the aforesaid operation until the desired number of 60 layers have been made to form a multi-layer body, and subjecting said multi-layer body to a treatment to form an integral unit having at least one surface of dense character.

6. The process of producing an integral paper 55 unit which comprises grinding cellulose fibers to form a hydrated .cellulose slippery mass having a fibrous structure, incorporating mineral filler in said mass in excessive amounts, applying said hydrated fibrousmass to a web of paper in wet 6 condition, and drying and calendering the aforesaid to produce an integral unit having a dense surface. I

'7. The process of producing an integral paper unit which comprises grinding'cellulose fibers to 05 form a hydrated cellulose slippery mass having a fibrous structure, precipitating a colloid within said hydrated mass, incorporating mineral filler in said mass in excessive amounts, applying said hydrated fibrous mass to a web of paper in wet 70 condition, and drying and calendering the aforesaid to produce an integral unit having a dense surface. 4

8. An improved integral paper unit comprising a web of paper having at least one face covered process for use in connection 5 with finely divided and hydrated cellulose of fibrous character containing a mineral filler.

9. An improved integral paper unit comprising a web of paper having at least one face covered with finely divided and hydrated mass of cellulose of fibrous character containing an vexcessive amount of mineral filler distributed therein.

10. An improved integral multi-layer paper unit comprising a plurality of layers of paper having a dense mixture of finely divided and hydrated mass of cellulose of fibrous character containing an excessive amount of mineral filler incorporated between said layers and on at least one outer face of said layers, said layers and said hydrated mass of cellulose of fibrous character being amalgamated together into an integial unit.

ERNST FUES. 

